5.5

CVE-2023-53246

In the Linux kernel, the following vulnerability has been resolved:

cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL

When compiled with CONFIG_CIFS_DFS_UPCALL disabled, cifs_dfs_d_automount
is NULL. cifs.ko logic for mapping CIFS_FATTR_DFS_REFERRAL attributes to
S_AUTOMOUNT and corresponding dentry flags is retained regardless of
CONFIG_CIFS_DFS_UPCALL, leading to a NULL pointer dereference in
VFS follow_automount() when traversing a DFS referral link:
  BUG: kernel NULL pointer dereference, address: 0000000000000000
  ...
  Call Trace:
   <TASK>
   __traverse_mounts+0xb5/0x220
   ? cifs_revalidate_mapping+0x65/0xc0 [cifs]
   step_into+0x195/0x610
   ? lookup_fast+0xe2/0xf0
   path_lookupat+0x64/0x140
   filename_lookup+0xc2/0x140
   ? __create_object+0x299/0x380
   ? kmem_cache_alloc+0x119/0x220
   ? user_path_at_empty+0x31/0x50
   user_path_at_empty+0x31/0x50
   __x64_sys_chdir+0x2a/0xd0
   ? exit_to_user_mode_prepare+0xca/0x100
   do_syscall_64+0x42/0x90
   entry_SYSCALL_64_after_hwframe+0x72/0xdc

This fix adds an inline cifs_dfs_d_automount() {return -EREMOTE} handler
when CONFIG_CIFS_DFS_UPCALL is disabled. An alternative would be to
avoid flagging S_AUTOMOUNT, etc. without CONFIG_CIFS_DFS_UPCALL. This
approach was chosen as it provides more control over the error path.
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Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version < 4.14.312
Linux ≫ Linux Kernel Version >= 4.15 < 4.19.280
Linux ≫ Linux Kernel Version >= 4.20 < 5.4.240
Linux ≫ Linux Kernel Version >= 5.5 < 5.10.177
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.106
Linux ≫ Linux Kernel Version >= 5.16 < 6.1.23
Linux ≫ Linux Kernel Version >= 6.2 < 6.2.10
Linux ≫ Linux Kernel Version6.3 Updaterc1
Linux ≫ Linux Kernel Version6.3 Updaterc2
Linux ≫ Linux Kernel Version6.3 Updaterc3
Linux ≫ Linux Kernel Version6.3 Updaterc4
Zu dieser CVE wurde keine CISA KEV oder CERT.AT-Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.02% 0.03
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-476 NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.